以全控型器件和PWM 技术为特征的二极管箝位多电平背靠背变换系统，能够实现能量的双向流动、有功功率和无功功率可独立控制、产生的谐波含量小、直流电压可控-Full PWM control type device and a diode clamp technique is characterized multi-level back-conversion system can achieve two-way flow of energy, active power and reactive pow